That's a heck of a jump cut from the "Let's go home" of the previous page. Did we miss something? A scene of the woman actually removing the hat, maybe?
Her hat was dirty and needed to be washed. Though not telling the yukkuri beforehand and handling her accessory carelessly and without her consent is generally a very bad thing to do, as their whole "identity" resides in the accessory and other yukkuri tend to despise and avoid accessoryless ones. So, unnecessary stress and all that.
It's probably just my imagination irritated by the huge amounts of pretendedly friendly yukkuri owners that turn out to be the most cruel of torturers (the Yuyuko series or the domestic Reimu, for all), but I get a faint creepy vibe from the woman in this series.
Yuwaaaaaah! Reimu and big sis are liaaaaars!Stop it! Give Marisa's Mister Hat back! I can't take it easy!The hatless stray Marisa hopped around the floor and protested.With her braid undone, even other yukkuri couldn't tell that the stray Marisa was a Marisa-type.I wanna take it eeeasyyyyy!